The present invention relates to a vehicular travel control system for performing automatic follow-up control for controlling own vehicle to follow-up a leading vehicle.
Conventionally, as a vehicular travel control system for performing automatic follow-up control for controlling own vehicle to follow-up a leading vehicle, it has been known a system for controlling travel of own vehicle for maintaining a following distance between the leading vehicle and the own vehicle at a preliminarily set following distance.
In such vehicular travel control system, when the leading vehicle is changed from a light or small-size vehicle to a heavy truck, the following distance between the leading vehicle and the own vehicle can be maintained constant unless a driver varies a set following distance value.
Therefore, when the following distance is set adapting to the case where the leading vehicle is light vehicle, and if the leading vehicle becomes the heavy truck, forward sight can be degraded to cause difficulty in comfortable drive.
Therefore, in the technology disclosed in Japanese Patent Application Laid-Open No. 2-40798 (1990), judgment is made whether the leading vehicle is a large size vehicle. If judgment is made that the leading vehicle is the large size vehicle, travel of own vehicle is controlled to provide longer following distance.
However, adequacy of the following distance which the driver feel, namely drivability representing adequacy of the current driving condition, such as easiness and sense of security which the driver feel, is not determined only by the kind of the leading vehicle. Namely, when a following vehicle which is own vehicle, is a standard passenger vehicle and the leading vehicle is the heavy truck, the driver of the standard passenger vehicle may feel that the following distance is shorter than that felt when the leading vehicle is the standard passenger vehicle even when the following distance is 5 m, for example. Conversely, when the leading vehicle is the standard passenger vehicle and the own vehicle as following vehicle is the heavy truck, the following distance can be felt longer than that felt when the leading vehicle is the heavy truck even when the following distance is 5 m, for example. Namely, even with the combination of the leading vehicle and the own vehicle as the following vehicle, the drivability to be felt by the driver of the own vehicle as following vehicle can be differentiate significantly.
Also, even by brightness of the environment, the drivability which the driver may feel at the following distance, becomes different significantly. Namely, in day and night, even when the following distance to the leading vehicle is the same, the following distance which the driver may feel, becomes different. That is, in the night where a field of vision is unclear, the following distance that the driver may feel, may be felt shorter.
On the other hand, similarly, even depending upon a traveling speed of the own vehicle, a relative speed relative to the leading vehicle, a relative position, a steering angle of the own vehicle and so forth, the drivability which the driver of the following vehicle may feel, becomes difference even when the following distance to the leading vehicle is the same.
It should be noted that as collection of results of research relating to a field of vision in driving, there is Surveillance Study Report relating to Following Distance (Following Time) of Commercial Vehicle, issued by Association of Electronic Technology for Automobile Traffic and Driving (March, 1999).
Therefore, an object of the present invention is to provide a vehicular travel control system which can perform automatic follow-up control for maintaining a following distance matching with drivability which a driver may feel.
According to the first aspect of the present invention, a vehicular travel control system comprises:
vehicle size detecting means for detecting size of a leading vehicle;
following distance detecting means for detecting following distance between a leading vehicle and an own vehicle;
insolation detecting means for detecting insolation around the own vehicle;
appropriate following distance calculating means for calculating an appropriate following distance;
travel control means for controlling travel of the own vehicle so that a following distance between the leading vehicle and the own vehicle detected by the following distance detecting means becomes an appropriate following distance derived by the appropriate following distance calculating means,
the appropriate following distance deriving means deriving the appropriate following distance so that the appropriate following distance becomes longer when the size of the leading vehicle detected by the vehicle size detecting means is large and the appropriate following distance becomes longer at higher brightness detected by the insolation detecting means.
According to the second aspect of the present invention, a vehicular travel control system comprises:
vehicle size detecting means for detecting size of a leading vehicle;
following distance detecting means for detecting following distance between a leading vehicle and an own vehicle;
speed detecting means for detecting a traveling speed as speed of own vehicle;
relative speed detecting means for detecting a relative speed of own vehicle relative to the leading vehicle;
relative position detecting means for detecting a relative position of the own vehicle relative to the leading vehicle;
steering angle detecting means for detecting a steering angle of the own vehicle;
insolation detecting means for detecting insolation around the own vehicle;
appropriate following distance calculating means for calculating an appropriate following distance;
travel control means for controlling travel of the own vehicle so that a following distance between the leading vehicle and the own vehicle detected by the following distance detecting means becomes an appropriate following distance derived by the appropriate following distance calculating means,
the appropriate following distance calculating means evaluating the size of the leading vehicle detected by the vehicle size detecting means, the steering angle detected by the steering angle detecting means, the insulation detected by the insolation detecting means, the traveling speed detected by the speed detecting means, the following distance detected by the following distance detecting means, the relative speed detected by the relative speed detecting means, the relative position detected by the relative position detecting means according to a preliminarily determined evaluation functions for deriving a current drivability as a result of evaluation and correcting the appropriate following distance derived depending upon the drivability.
According to a third aspect of the present invention, a vehicular travel control method for controlling a following distance between a leading vehicle and an own vehicle comprises:
first step of detecting a size of the leading vehicle, the following distance between the leading vehicle and the own vehicle and an insolation around the own vehicle;
second step of deriving an appropriate following distance to be longer at greater size of the leading vehicle detected at the first step and to be longer at higher brightness detected at the first step; and
third step of controlling travel of the own vehicle so that the following distance between the leading vehicle and the own vehicle detected at the first step becomes the appropriate following distance derived at the second step.